import { fetch } from "undici";

/**
 * Response structure for Livebox login API.
 */
interface LoginResponse {
  data?: {
    contextID: string;
  };
}

/**
 * Handles authentication for Livebox API.
 */
export class AuthManager {
  private hostname: string;
  private username: string;
  private password: string;
  private contextID?: string;
  private cookie?: string;

  constructor(hostname: string, username: string, password: string) {
    this.hostname = hostname;
    this.username = username;
    this.password = password;
  }

  /**
   * Logs in and establishes session.
   */
  async login(): Promise<void> {
    const response = await fetch(`http://${this.hostname}/ws`, {
      method: "POST",
      headers: {
        "Content-Type": "application/x-sah-ws-4-call+json",
        Authorization: "X-Sah-Login",
      },
      body: JSON.stringify({
        service: "sah.Device.Information",
        method: "createContext",
        parameters: {
          applicationName: "webui",
          username: this.username,
          password: this.password,
        },
      }),
    });

    const json = (await response.json()) as LoginResponse;
    const cookieHeader = response.headers.get("set-cookie");

    if (!json.data?.contextID || !cookieHeader) {
      throw new Error("Login failed - check your credentials");
    }

    this.contextID = json.data.contextID;
    this.cookie = cookieHeader.split(";")[0];
  }

  /**
   * Gets auth headers for requests.
   */
  getAuthHeaders(): { Authorization: string; Cookie: string } {
    if (!this.contextID || !this.cookie) {
      throw new Error("Not authenticated - call login() first");
    }
    return {
      Authorization: `X-Sah ${this.contextID}`,
      Cookie: this.cookie,
    };
  }

  /**
   * Checks if authenticated.
   */
  isAuthenticated(): boolean {
    return !!this.contextID && !!this.cookie;
  }
}